Air gauge



April 19, 1932- B. D. BOENKER E1' AL 1,855,088

AIR GAUGE Filed Nov. 24, 1928 NVENTORS Etalon D..Ba e nner WITNESS and 711801Z ATTORN EY Patented Apr. 19, 1932 i l 1,855,088

UNITED STATES .PATENT OFFICE d BENTON D. BOENKER AND WILLIAM S. HUTCHIN'SON, OF ST. LOUIS, MISSOURI, AS-

SIGNORS OF ONE-THIRD TO RAYMOND B. .NAES, OF ST. LOUIS, MISSOURIV i AIR GAUGE Application filed November 24, 1928.V Serial No. 321,669.

Our invention relates to pressure gauges bushing 9 having screw threaded engagefor pneumatic tires. ment with aV conventional tire stem 10 at the An object of the same is to provide a presupper end thereof which has threaded ensure gauge whereby the pressure in a pneugagement with the nut 8. v

' matic tire may be read at all times and will Formed with the bottom Vof the casing andn permit the passage of air into the tire from extending longitudinally and centrally a suitable source of pressure or the release thereof .is a post 11 having a longitudinal of the tire pressure from the latter when debore 12 extending its entire length. .At its sired. upper end, this bore 12 is enlarged and rew The invention further provides an air ceives a conventional check valve 13 which .55 gauge which is permanently associated with is normally closed to the atmosphere. At its the usual pneumatic tire stem and is of such lower end, this bore `12 communicates with construction as to reduce its liability to a by-pass 14. provided in the bottom'ofthe breakage to a minimum. cylinder and leading from the hollow nipple.

i Another object of the invention is to pro- The by-pass 14 communicates with a conduit 66 vide a pressure gauge of this character which 15 formed in an upstanding enlargement 16 will normally hold the usual check valve in cast with the inner face of the bottom of the the tire stem in open position to permit tire cylinder. i y pressure to be communicated to a pressure For the purpose of indicating the pressure from the tire stem will permit the check valve 10 projects, a pressure responsive element in to seat in the usual manner thus preventing the form of a helically coiled resilient tube the loss of tire pressure. I 17 is provided. The coiled tube 17 encircles With the preceding and other objects and the post 11 and has its lower extremityweldgy, advantages in mind, the invention consists in ed or otherwise secured tothe enlargement 70 the novel combination of elements, construc- 16 and communicating with'theconduitv 15. tions and arrangements of parts and opera- Theopposite end of the coiled tube is closed tions to be hereinafter specifically referred so that when vpneumatic pressure flows into to, claimed and illustrated in the accompanythe tube, the latter will be expanded -acof, indicator mechanism, but when removed contents of a tire tube, from which the-stem .65.,

gn ing drawings, wherein: cordng to the air pressure contained inthe 5.

Figure 1 is a fragmentary side elevation tire tube. Fixed to the upper end-mostv conof a pneumatic tire having our invention asvolutions of the tube is a laterally extending sociated therewith; L-shaped indicating linger 18 which is mov- Figure 2 is a longitudinal sectional view of able over a lsemi-circular graduated scale 19 the same taken on line 2-2 of Figure 1; and disposed to one side of a semi-circular slot or L80 Figure 3 is a transverse section taken on sight opening 20 provided in the upper end line 3--3 of Figure 2. of the cylinder.

Referring to the invention in detail, a cyl- The scale 19 is formed with an offset atinder 5 whose bottom is formed with a hollow taching portion 21 which is secured Vto the central nipple 6 terminating in an annular walls of the cylinder below thev opening 191985 flange 7 is provided. A flanged nut 8 is soas to support the scale in spaced relation loosely received on the nipple and held to the cylinder walls so that the verticalleg against displacement therefrom by the annuof the indicating element may move between y. lar flange 7. Cooperating with the nut 8 in the scale and cylinder walls; e Y.

holding the casing in operative position is a In order to'permit pneumatic pressure toDO Viiow from the valve stem l and into the coiled tube, a boss 22 is formed upon the under face of the` cylinder bottom and is located centrally of the hollow nipple to engage the kusual check valve a in the tire stem to hold the latter in open position.

In order to preclude the passage of dirt Y and other foreign matter into the cylinder by Way of the slot 20, a relatively heavy glass annulus 23 is received in the upper end of the cylinder in transverse alinement with the slot 20. The glass annulus 23 is clamped be- Y tween an annular internal shoulder 24 provided upon the interior of the cylinder and a closure cap 25' having threaded engagement l with the cylinder. Packing elements 26 are arranged upon the opposite faces of they annulus to protect the same against breakage.

A central threadedopening 27 is providedin j the closure and lhas threaded engagement *with the threaded projecting end 28 of the post to lend rigidity to the vlatter at this point. ,Y

With a tire gauge vthus constructed, the pneumatic pressure will be always Icommunicated to the pressure responsive element and thus indicate the tire Vpressure at all times.

, When it is desired to increase the tire pressure, the 'usual air hose chuck is positioned on the projecting end 28 of the post vand in so doing, the valve 13 `is depressed to allow air pressure to pass through the bore l2 and into the tire stem. In the event that it is desired to release some of the pressure from the tire, the valve 13 will be held depressed in the usual manner.

`What is claimedis: l. In an air pressure indicator for pneu- 'matic tires,v an yelongated tubular casing adapted to be positioned on the tire stem and having means forl holding the valve thereof in open postio'n,the casing having a by pass at one end which lis adapted to open'into the tire stem, a helically rcoiled pressure responsive tube in the casing and extending substantially the entire length thereof and having one end closed and its other end open and communicating with the by pass, a pressure indicating finger fixed to the pressureV responsive tube adjacent its closed end, and a Vgraduated scale opposed to the finger and over which the latter moves.

2. In an air pressure indicator for pneumatic tires, an elongated tubular casing adapted to be positioned on the tire stem and having means for holding `the valve thereof Y in open position,` the casing having a by-pass at one end which is adapted to open into the tire stein, a helically coiled pressure responsive tube in the casing and extending substantially the entire length thereof and havingone end closed and its other end open and in communication with rsaid by-pass, an arcuate shaped graduatedv scale carried withy V13oY los i 

